There's no such thing as an "impression" when it comes to reliability, just statistics.

Since anyone on an internet forum would be making up results out of thin air, or based on claims like consumer reports, etc, it's not worth having a discussion.

If you asked a BMW quality engineer, I'm going to take a guess and say yes, the N55 is more reliable. Why? Because they sat there for 4 years and analyzed all the failures on the N54 and redesigned it to improve the quality (go Six Sigma!).

Both engines are good IMO. The main difference is the exhaust. The new N55 engine has one exhaust pipe the feeds from all 6 cylinder (for less fuel consumption) while the N54 had 2 pipes, one feeding from cylinders 1, 2, and 3 and another pipe feeding from cylinders 4, 5, and 6.

The N55 is only as reliable as the one BMW built for you. And how well you take care of it.

Overall the N54 is a more complicated design. It also has some higher end components such as the piezo injectors and true dual turbos. N55 is what most would consider a cost reduced version of the N54.

The N55 is only as reliable as the one BMW built for you. And how well you take care of it.

Overall the N54 is a more complicated design. It also has some higher end components such as the piezo injectors and true dual turbos. N55 is what most would consider a cost reduced version of the N54.

that is so true...

I took my car in for service this morning, to replace the fabled Rusty Seat Frames and deal with some minor squeaks.

The Loaner F30 328xi they gave me, mind you with 10 miles on the odo, threw an alert after driving for 5 miles that the engine oil pressure is too low...BRAND NEW 328xi and already has issues.

I'm unsure I'll own another BMW after this one, given how hit or miss their build quality has been thus far...they loaned me a E90 328i, with 11k on the odo, nary an issue. The steering feel is pretty nice too....

I took my car in for service this morning, to replace the fabled Rusty Seat Frames and deal with some minor squeaks.

The Loaner F30 328xi they gave me, mind you with 10 miles on the odo, threw an alert after driving for 5 miles that the engine oil pressure is too low...BRAND NEW 328xi and already has issues.

I'm unsure I'll own another BMW after this one, given how hit or miss their build quality has been thus far...they loaned me a E90 328i, with 11k on the odo, nary an issue. The steering feel is pretty nice too....

So you had an issue on a First year new model car but not an issue on a car in it's 6th year of the build cycle(e90).....

So you had an issue on a First year new model car but not an issue on a car in it's 6th year of the build cycle(e90).....

it's a 2013, so technically a second year build.

There's NO excuse for an engine issue like low oil pressure on a new car - even if the sensor is faulty because it was below freezing and the oil hadn't warmed up, if the warning WAS correct, I would've grenaded the engine. That's pathetic.

There's NO excuse for an engine issue like low oil pressure on a new car - even if the sensor is faulty because it was below freezing and the oil hadn't warmed up, if the warning WAS correct, I would've grenaded the engine. That's pathetic.

Actually, Xdrive cars first started as 2013 model years. and the N20 has been around for a while now.

Regardless, there are always going to be a few bad apples.

Any other car manufacturer has similar issues. Not every car is going to be perfect.

I know this has probably been beaten to death, but would like to know first hand impressions.

To me its more like what are you willing to put up with?

HPFP faliures on these cars or driving around a P car with intermediate shaft that is a ticking time bomb and ready to grenade at any given moment without notice, wich by the way a crate motor from Porsche is 19k.

Yeah Id take the HPFP problems 2-3 hours at the dealer and youre on your way

Honestly no one knows yet if n55 is better. So far so good, but it has its own share of small issues.

Actually, Xdrive cars first started as 2013 model years. and the N20 has been around for a while now.

Regardless, there are always going to be a few bad apples.

Any other car manufacturer has similar issues. Not every car is going to be perfect.

I don't doubt it, but it's still comical/ironic that I take my car in for issues, get a loaner, and the loaner has issues.

So far, knock on wood, I've only had surface/cosmetic type issues with my 335i - engine has been strong (so far only consumed a quart of oil in 7500 miles), suspension has been awesome (after the upgrade), brakes haven't squealed, and I've enjoyed 28-30 mpg.

I just wonder what troubles are coming down the pike...or if I'm in the clear. Was one reason why I got the 100k warranty, once I started having problems, I wanted some peace of mind.

The N55 is only as reliable as the one BMW built for you. And how well you take care of it.

Overall the N54 is a more complicated design. It also has some higher end components such as the piezo injectors and true dual turbos. N55 is what most would consider a cost reduced version of the N54.

The N54 also uses forged pistons, not cast ones, among some other things I can't recall this late at night. If you were going to go nuts out and tune your car significantly, I'd pick an N54 engine over the N55.

OP -If you're just a daily driver with ambition, it's not going to matter to you.

Overall I would recommend reading the data sheet for the engine to determine the differences yourself and make your own call. I will try to attach a copy. When discussing reliability it appears that the connecting rods to the pistons have been redesigned to better distribute the load placed on them. The VANOS oil passages in the engine are less complex, the oil management of the engine has had multiple overhauls compared to the n54 with changes to the crankcase and oil pan, and oil pump. It mentions that the HPFP is still the same design as the N54, and covers the difference in the fuel injectors from the Piezo-electric ones to Bosch.

Overall I would be willing to bet that the N55 would be more reliable as mentioned earlier for the simple fact that they took data from the N54 and improved upon many systems. I can't say whether or not the change in forged parts will affect reliability when tuned. Seeing as the engine is currently having issues reaching 400hp due to the twin scroll turbo limitations I doubt you will ever run into power levels that would make these parts a necessity. That is speculation tho. Only time will really tell